Air line vapor trap

ABSTRACT

An in-line vapor trap for removing water and/or oil vapor from a compressed air line which includes a manifold having spaced coaxial inlet and outlet openings, a hollow base suspended from the manifold, and replaceable cartridges connecting the manifold inlet to the hollow base and connecting the hollow base to the manifold outlet. A honeycomb structure is disposed in the lower portion of the base within the enclosed volume defined thereby, and cooperates with the base side and bottom walls to define a zone of substantially zero air movement for collection of liquid droplets. A depression in the base bottom wall forms a liquid sump, and a drain opens into the sump for drainage of captured liquid. This drain features an enclosed bowl suspended by a hollow fitting beneath the sump, and an aspiration tube which extends from within the bowl through the fitting and sump to adjacent the exit from the hollow base, such that air is circulated from within the base through the fitting into the bowl and then aspirated therefrom through the tube. Liquid collected in the sump is drawn by such air circulation into the bowl.

This is a continuation of application Ser. No. 726,760 filed Jul. 8,1991 now abandoned which is a continuation of Ser. No. 07/402,809, filedSep. 5, 1989, which will issue as U.S. Pat. No. 5,030,262 on Jul. 9,1991, which is a continuation of application Ser. No. 07/188,638, filedMay 2, 1988 (now U.S. Pat. No. 4,874,408), which is a file wrappercontinuation of application Ser. No. 07/115,416, filed Nov. 2, 1987 nowabandoned.

The present invention is directed to devices of a type adapted to removeoil and/or water vapor from a flowing gaseous medium such as compressedair, and more particularly to improved drainage of devices of thischaracter.

U.S. Pat. No. 4,487,618 assigned to the assignee hereof discloses anin-line trap for removing water and/or oil vapor from a compressed airline which includes a manifold having spaced coaxial inlet and outletopenings and a hollow base suspended from the manifold A first cartridgeextends between the manifold inlet and the enclosed volume within thehollow base, and contains a wire pad adapted to coalesce water and/oroil vapor in air passing therethrough into droplets which are thenentrained by the air and carried into the base volume An integralhoneycomb structure cooperates with the bottom and side walls of thebase to form a dead airspace which captures water droplets falling fromair entering the enclosed volume from the first cartridge. A secondcartridge, which includes spirally wound fiber and wire mesh materials,directs compressed air from within the enclosed base volume to themanifold outlet and simultaneously functions to remove any remainingvapor therefrom.

In a commercial embodiment of the device disclosed in the referencedpatent marketed by applicant's assignee under the trademark EXTRACTOR, adepression in the bottom wall of the base forms a liquid sump forcollection of water and/or oil removed from the compressed air. Aconventional drain mechanism, including a T-shaped draincock, is mountedin the base wall depression for selectively draining liquid collectedtherein. U.S. Pat. No. 4,600,416 discloses an improvement upon suchcommercial device in which the drain features an open annular orificefor continuous weep-drainage of liquid under pressure The orificesurrounds a wire having an angulated head disposed within the sump. Thewire may be rotated by an operator so as to remove dirt and debris fromsurrounding and clogging the annular weep orifice.

Although the devices hereinabove described have enjoyed substantialcommercial acceptance and success, improvements remain desirable Inparticular, the continuously-open weep drain causes a significant andundesirable loss of air pressure Furthermore, liquid ejected from thetrap puddles or pools beneath the weep drain, which is often undesirablein a manufacturing environment. It is therefore a general object of thepresent invention to provide an air line vapor trap of the describedcharacter which features an improved drain structure for continuouslyand automatically draining liquid collected in the trap sump withoutsubstantially reducing pressure in the main air line and withoutspraying the liquid into the surrounding environment.

In accordance with the present invention, an air line vapor trap of thedescribed type is characterized in that a second enclosure is suspendedby an open fitting beneath the drain sump, and a hollow tube extendsfrom within the second enclosure through the fitting and sump to theentrance to the second cartridge. Air is thus aspirated through the tubefrom within the second enclosure so as to draw liquid from the sumpthrough the fitting into the second enclosure. In a preferred embodimentof the present invention, the tube is carried by a collar mounted withinthe second enclosure beneath the fitting and communicates with a centralopening in such collar. An array of drain openings surround the centralopening in the collar, and an axially and radially flared skirtsurrounds the central opening and is positioned beneath the array ofdrain openings. Liquid drawn through the drain array into the secondenclosure thus impinges upon and drips from the skirt, and is notreaspirated through the central opening and tube into the trap. A floatdrain or the like is carried at the lower portion of the secondenclosure for periodically draining liquid collected therein to asuitable collection tank or the like.

The invention, together with additional objects, features and advantagesthereof, will be best understood from the following description, theappended claims and the accompanying drawing in which:

FIG. 1 is an elevational bisectional view taken in a vertical planethrough the vapor trap in accordance with a presently preferredembodiment of the invention;

FIG. 2 is a fragmentary view of the trap in FIG. 1 featuring a portionof the drain mechanism on an enlarged scale;

FIGS. 3 and 4 are sectional views taken substantially along therespective lines 3--3 and 4--4 in FIGS. 2 and 1; and

FIG. 5 is a view similar to that of FIG. 3 but illustrating a modifiedembodiment of the invention.

The disclosures of above-noted U.S. Pat. Nos. 4,487,618 and 4,600,416are incorporated herein by reference.

FIG. 1 illustrates a presently preferred embodiment 10 of a vapor trapin accordance with the invention as comprising a cap or manifold 12having oppositely directed and coaxially aligned internally threadedopenings 14,16 respectively defining an inlet and outlet adapted forin-line connection to a gas line such as a compressed air line. Aconcave internal surface 18 on manifold 12 internally opposed to inletopening 14 directs inlet air orthogonally of the inlet axis, ordownwardly in the orientation of FIG 1. In the same manner, a concavesurface 20 opposed to outlet opening 16 receives and directs upwardlyflowing air to outlet opening 16. A hollow base 22 of generallyrectangular construction comprises a bottom wall plate 24 and acontinuous sidewall 25 peripherally contiguous with bottom wall plate 24and separated therefrom by the gasket 26. Base 22 thus forms an enclosedvolume 28 suspended beneath and fastened to manifold 12 by the bolts 30.A pair of laterally spaced circular openings 32,34 are formed in base 22in respective alignment in assembly with the inlet and outlet ofmanifold 12. An integral honeycomb structure 36 is disposed in the lowerportion of enclosed volume 28 adjacent to bottom wall plate 24 andcooperates with the side and bottom walls of enclosure 22 to define azone of substantially zero air movement adjacent to the enclosure bottomwall.

A pair of laterally spaced replaceable vaporizer cartridges 38,40 areclamped by bolts 30 between manifold 12 and base 22 in sealingengagement therewith. Cartridge 38, which is clamped in axial alignmentbetween the inlet section of manifold 12 and opening 32 in base 22,comprises a cylindrical cartridge case 42 and an axially spaced pair ofopen end qaskets 44 clamped in sealing engagement with manifold 12 andbase 22 respectively Within case 42, cartridge 38 comprises a mass orpad 48 of wire mesh fibers of a type adapted to coalesce water or oilvapor passing therethrough into vapor droplets. Pad 48 in the preferredembodiment of the invention comprises a so-called "Goodloe columnpacking" of a type disclosed in U.S. Pat. No. 2,521,785. The dimensionof cartridge 38 cross-sectional to air flow is substantially less thanthat of the enclosed volume 28 within base 22. Cartridge 40, which isclamped in axial alignment between the outlet portion of manifold 12 andbase opening 34, comprises an outer cylindrical case 50 and a pair ofend gaskets 44,45 in respective sealing engagement with manifold 12 andbase 22. Within cartridge case 50 and between end gaskets 44,45, andfilling the entire cartridge volume, is a plug structure 52 of absorbentfabric interwoven with strengthening wire threads.

In operation of trap 10, which is similar in most important respects tothat disclosed in U.S. Pat. No. 4,487,618 to the extent thus fardescribed, air with entrained water and/or oil vapor is received throughinlet opening 14 and directed by surface 18 downwardly into and throughcartridge pad 48. During such passage through pad 48, the water and/oroil vapors are coalesced into droplets which are entrained in theflowing air mass and carried thereby into the open volume 28 within base22 Since the cross-sectional dimension to air flow within volume 28 isgreater than that within cartridge 38, the velocity of air entering theopen base is reduced, and the entrained droplets fall by gravity andcentrifugal force toward the lower portion of the base Such droplets arecaptured within the essentially dead airspace formed by honeycombstructure 36. Since the construction of honeycomb structure 36 preventssubstantial air movement therewithin, revaporization is substantiallyeliminated In the meantime, the compressed air stream, which is now 75%to 95% dry, is fed from enclosed volume 28 through opening 34 intocartridge 40. As the air passes upwardly through the fiber/mesh plug 52toward outlet 16, any remaining vapor is removed by the fibrous plugmaterial. A depression 60 is formed in bottom wall plate 24, beneathhoneycomb structure 36 and the dead air space provided thereby, to serveas a sump for liquid removed from the compressed air stream.

In accordance with the present invention, sump 60 is positioned beneathopening 34 coaxially therewith An enclosure 62 is suspended from sump 60by the hollow fitting 64 which is threadably received into acorresponding opening in sump 60. Enclosure 62 comprises a bowl 66having an open edge suspended from the periphery of an enclosure top 68.Top 68 has a central opening 70 into which the lower end fitting 64 isthreadably received Opening 70 is outwardly and downwardly flared, asbest seen in FIG. 2, and has a collar 72 threadably received thereinfrom within enclosure 62 coaxially with fitting 64. Collar 72 has acircular central passage 74, and has a circumferential array of passages76 extending axially therethrough surrounding central passage 74. Arigid tube 78 is press-fitted into a counterbore in central passage 74and extends upwardly through opening 70, fitting 64, sump 60 andhoneycomb 36 to terminate at opening 34 (FIG. 1) coaxially therewith Aconical skirt 80 integrally depends from collar 72 surrounding centralopening 74 and flares axially and radially therefrom beneath passages76.

In operation, air flowing from within enclosed volume 28 through opening34 to cartridge 40 exhibits increase in velocity due to decrease ineffective cross-sectional area. In this respect, it will be noted inFIG. 1 that the air-passage opening 34 and the central opening in gasket45 are smaller than opening 32 and the corresponding passage in gaskets44 in order to enhance such velocity increase. Air is aspirated upwardlythrough tube 28 and central passage 74, which thus draws a small amountof air from within volume 28 through fitting 64 surrounding tube 78 andthrough openings 76 into enclosure 62. Such air flow through fitting 64draws liquid from sump 60 through opening 70 and through openings 76 incollar 72. Such liquid impinges upon and drips from skirt 80, which thusprevents flow of liquid along collar 72 and re-aspiration through tube78. A float drain or other conventional device 81 is positioned at thelower end of bowl 66 for periodically draining liquid therefrom into asuitable collection tank or the like (not shown).

FIG. 5 illustrates a modified collar 72a wherein the multiplicity ofcircular opening 76 in the embodiment of FIG. 3 are replaced by a pairof kidney-shaped openings 76a extending at constant radius aroundcentral opening 74. FIG. 4 illustrates an improvement in manifold 12whereby ribs 82 extend from surface 20 and thus help support gasket 44against pressure surges in air passing through the vapor trap. FIG. 1also illustrates a further improvement in the prior art trapshereinabove described whereby a baffle 84 projects downwardly from thecentral boss 86 within enclosed volume 28 for promoting downwardcirculation of air toward honeycomb 36.

The invention claimed is:
 1. An assembly for draining liquid from an airtreatment unit which includes means for directing a flow of compressedair, means for coalescing liquid from vapor entrained in the flow ofcompressed air, and means for collecting liquid coalesced by thecoalescing means in a sump, the assembly comprisingenclosure means fordefining an enclosed volume, aspirator tube means for using compressedair flowing in the directing means to develop negative pressure in theenclosed volume, the aspirator tube means interconnecting the enclosuremeans and the directing means, and means for conducting liquid collectedin the sump into the enclosed volume in response to suction generated bythe negative pressure developed in the enclosed volume, the conductingmeans interconnecting the collecting means and the enclosure means. 2.The assembly of claim 1, wherein the enclosure means includes a hollowvessel formed to include an inlet coupled to the conducting means and anoutlet and means in the hollow vessel for periodically draining liquidfrom the hollow vessel through the outlet thereof.
 3. The assembly ofclaim 1, wherein the aspirator tube means includes an aspirator tubehaving an open mouth at one of its ends communicating with the flow ofcompressed air in the directing means and an open mouth at the other ofits ends communicating with the enclosed volume.
 4. The assembly ofclaim 3, wherein the conducting means includes a hollow fittingconnecting the directing means to the enclosure means, the hollowfitting is formed to include a liquid-conducting passage extendingtherethrough, and the aspirator tube extends through theliquid-conducting passage communicate with the enclosed volume.
 5. Theassembly of claim 4, wherein the hollow fitting is externally threadedand the enclosure means includes an inlet port that is internallythreaded to connect to the external threads on the hollow fitting tocouple the enclosure means to the hollow fitting.
 6. The assembly ofclaim 1, wherein the enclosure means includes a hollow vessel formed toinclude an open mouth and provide the enclosed volume, and theconducting means extends to the open mouth to interconnect the sump andthe enclosed volume in fluid communication.
 7. The assembly of claim 6,wherein the hollow vessel further includes means for threadably engagingthe air treatment unit so that the hollow vessel is connectable to theair treatment unit to position the open mount in fluid communicationwith the conducting means.
 8. The assembly of claim 1, wherein the airtreatment unit includes a bottom portion underneath the collecting meansand a threaded fitting appended to the bottom portion and formed toinclude a passageway extending therethrough, the engaging means isconfigured to threadably engage the thread fitting, and the conductingmeans extends into the passageway formed in the threaded fitting toempty liquid collected in the sump into the enclosed volume formed inthe underlying hollow vessel.
 9. The assembly of claim 1, wherein theenclosure means further includes fitting means for suspending the hollowvessel from the air treatment unit.
 10. The assembly of claim 9, whereinthe fitting means is formed to include a liquid-conducting passagetherethrough interconnecting the conducting means and the enclosedvolume.